Materials with different properties like texture, construction, opacity, and so on reflect light differently. Thus, when the same colorant is applied to materials with different properties the two colored materials may have different appearances. For example, a first shade of blue paint, applied to a substantially smooth surface may have a different appearance than the same shade of blue paint when applied to a textured surface. Similarly, a first shade of red dye may yield a first appearance when applied to a cotton knitted garment and a second appearance when applied to a cotton woven garment. Apparent color mismatches are also evidenced in color matching that attempts to cross product lines. For example, a first shade of green may have a first appearance on a football jersey, a second appearance on a poster promoting the team with the green jerseys, a third appearance on a toy rubber football promoting the team with the green jerseys, a fourth appearance on a promotional foam finger, a fifth appearance on a team key chain, a sixth appearance on a cotton baby outfit, and so on. Ideally, to enhance marketing and promotion, the green would appear substantially identical on all products, regardless of the material and/or substrate on which the color appears.
Matching colors on materials with different properties has historically been undertaken in applications including, but not limited to, textile dyeing, leather tanning, leather dying, plastics master-batching, coatings, point of sale paints, trade sale paints, wood stains and so on. Typically, color matching on materials with different properties has relied on a human technician applying intuition, experience and ad hoc methods. Thus, varying results may be attained due to the varying levels of technician experience, skill, visual capacity for discerning color differences, and estimating—based on experience in color matching—the combination and proportions of colorants employed to match a color on two or more substrates. By way of illustration, a color formula for a latex paint may be an ideal match when the paint is applied to a flat, non-porous surface. However, when the same latex paint is applied to a highly textured surface, it will appear to be unacceptably off-color. Commercially this causes customer complaints, returns and so on.